In general, plastic containers, which are formed easily and manufactured at lower costs, are widely used for various applications. However, putting viscous contents such as mayonnaise-like food within a plastic container causes the contents to easily stick on the inner wall surface of the container, resulting in a failure of using up the contents without leaving the contents within the container.
In recent years, coating agents for improving the slipping down of contents have been developed. It is known that applying such a coating agent on the inner wall surface of the container improves the slip characteristic of the inner wall surface of the container, allowing contents within the container to be used up easily.
In this regard, a possible approach to applying the coating agent uniformly on the inner wall surface of the container is to insert a nozzle as disclosed in Patent Literature 1 into the interior of the container and eject the coating agent while rotating the container.